1. Field of the Disclosure
The present disclosure relates to electronic devices and processes for forming electronic devices and, more particularly, to electronic devices including selectively formed layers.
2. Description of the Related Art
Successful manufacturing of semiconductor devices can depend in part on the precision with which patterned layers can be located during the manufacturing process. Blanket formation of a layer followed by lithography and etch is one method that can be used. However, precise location using a physical alignment mark may prove challenging with thick or opaque layers.
One proposed method is to use a process that will deposit or grow material only where a specific material is exposed on the surface of a workpiece. Such a selective process can form a layer according to an exposed pattern the specific material without the subsequent use of lithography. However, the growth of an individual feature using such a process can be sensitive to the size and proximity of other features. For example, during a process, a first feature surrounded by other features can grow to a different size than a second feature of a substantially same size and shape as the first feature in an open area. To cope with this local loading, a separate formation process may need to be tailored for each layer grown.
Another method can use previously existing dummy features, such as CMP tiles to help even out the local loading during the process. A density of the dummy features that are already present can limit such a method. If the density of the dummy features is too low, exposing all of the dummy features may not adequately compensate for the process difference. If the density of the dummy features is too high, an additional lithography and etch step to uncover only those tiles that are desired may be required to avoid over compensating for the process difference.
Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the invention. The use of the same reference symbols in different drawings indicates similar or identical items.